The present invention relates to a ventilator for an ignition distributor used with an internal combustion engine for an automobile, and particularly to a ventilator for an ignition distributor which has improved ventilation properties.
In general, large amounts of ozone and nitrogen oxides are produced in an ignition distributor of an automobile by the spark discharge generated between a fixed electrode which is provided on a distribution cap and a distribution rotor which rotates together with the rotation of the engine. When these substances react with water, nitric acid is produced. The ozone and nitric acid corrode the components of the distributor, and thus hinder the working of the distributor.
Therefore, a technique, for instance, as disclosed in Japanese Patent Laid-Open No. 4869/1986 is known as a structure for ventilating a distributor, in which ventilation is provided by means of a plurality of holes communicating the inside of a distributor with the outside thereof in order to exhaust the internal air which contains harmful gases and which is rotated by the rotor in the distributor.
The above-described conventional communicating holes have disadvantages i that, since an internal opening portion of each communicating hole is formed substantially at right angles to an external opening portion thereof and the ventilation resistance of air is therefore large, the ventilation efficiency is decreased, the flow of air is discontinuous, and the dust passing into the communicating holes stays at the bends therein.